Actuators for Implantable Devices: A Broad View

Abstract

The choice of actuators dictates how an implantable biomedical device moves. Specifically, the concept of implantable robots consists of the three pillars: actuators, sensors, and powering. Robotic devices that require active motion are driven by a biocompatible actuator. Depending on the actuating mechanism, different types of actuators vary remarkably in strain/stress output, frequency, power consumption, and durability. Most reviews to date focus on specific type of actuating mechanism (electric, photonic, electrothermal, etc.) for biomedical applications. With a rapidly expanding library of novel actuators, however, the granular boundaries between subcategories turns the selection of actuators a laborious task, which can be particularly time-consuming to those unfamiliar with actuation. To offer a broad view, this study (1) showcases the recent advances in various types of actuating technologies that can be potentially implemented in vivo, (2) outlines technical advantages and the limitations of each type, and (3) provides use-specific suggestions on actuator choice for applications such as drug delivery, cardiovascular, and endoscopy implants.

Smart Healthcare: Exploring the Internet of Medical Things with Ambient Intelligence

“…For instance, sensors such as blood glucose monitors measure the body's blood glucose levels, while actuators respond by regulating insulin levels. These actuators can be categorized into body-centric actuators [51] and environment-centric actuators. Body-centric actuators can be further classified into therapy (therapeutic), diagnosis (diagnostic), and treatment actuators [52].…”

“…Surgical robot actuators, for instance, enable precise and controlled movements during surgical procedures, enhancing surgical outcomes and patient safety. Drug delivery pump actuators regulate the flow rate of medication administration, ensuring accurate dosage delivery to patients [51]. Similarly, infusion pump actuators facilitate the controlled infusion of fluids into patients' circulatory systems, which is vital for administering medications and nutrients.…”

“…Radiology table actuators enable precise positioning of patients during imaging procedures, ensuring optimal imaging quality while prioritizing patient comfort and safety. Rehabilitation robot actuators support physical therapy and rehabilitation exercises, providing varying levels of resistance and assistance to patients undergoing rehabilitation [51]. Despite their indispensable roles, these actuators pose challenges related to accuracy, compatibility, safety, and integration with existing healthcare systems.…”

Actuation for flexible and stretchable microdevices

“…Wearable and implantable devices in biomedical applications require microdevices to conform to the human body for real-time diagnosis and treatments. 31 Therefore, the actuator structures inside the device must be highly flexible and stretchable for comfortable attachment to the body. 32 Besides, fluid manipulation at the microscale through microvalves and micropumps is facilitated by pneumatically or hydraulically deforming flexible and stretchable microstructures.…”